The literature is inconclusive on the accuracy of various thermometer devices used in clinical practice. We conducted a meta-analysis on the accuracy of temperatures from six peripheral (non-core) thermometer devices compared to core body temperature. Medline, CINAHL, and other resources were searched for articles related to body temperature and thermometer devices. From 197 articles, 159 were research and 38 were non-research. Thirty-four research articles met criteria for inclusion in the meta-analysis: core and non-core temperatures measured concurrently or sequentially, appropriate statistics, and sample size of 10 or more. We applied Cochrane GRADE criteria for diagnostic tests and strategies. Assessments of bias, indirectness of evidence, overall confidence in effect sizes, consistency, precision, and publication bias indicated low risk. The extent of heterogeneity was Q=0% for each type of thermometer device; impact of heterogeneity was 0% due to true differences, and I 2=100% due to random sampling error. Forest plots illustrated bias (mean differences), 95% confidence limits, and confidence intervals (CI). A forest plot of the overall accuracy of non-core devices indicated that oral and rectal electronic thermometers had the least bias (-0.05°C and -0.04°C) and nar- rowest CI: oral=0.58°C, rectal=1.18°C, compared to temporal (1.88°C), axillary chemical (2.25°C), axillary electronic (2.36°C), and tympanic (2.62°C). Our findings indicate that only oral and rectal electronic thermometer devices should be used to measure temperature of individuals for screening, monitoring, diagnostic, and treatment decisions. Tympanic, temporal, axillary chemical, and axillary electronic thermometer devices should not be used in clinical practice. [ABSTRACT FROM AUTHOR]